Color oscillograph recording paper

ABSTRACT

Light-sensitive multicolor recording paper for oscillograph traces, having on a support, an undercoat of green-sensitive gelatin-silver bromoiodide emulsion in which the iodine amounts to 0.2-2.0 mol percent of the silver and containing a magenta color former, a gelatin interlayer, an overlying blue-sensitive gelatin-silver bromoiodide emulsion in which the iodine is 4-12 mol percent of the silver content and containing cyan color former, and a gelatin surface coating. By using yellow and magenta filters of different density for the exposing light and subjecting the material to color development, at least three different color traces can be produced.

It'll I it i [72] Inventors CarlE.Johnson;

Dewey M. Dumers, both of lBinghamton, N.Y. [21] Appl. No. 544,812 [22]Filed Apr. 25, 1966 [45] Patented Oct. 26, I971 [73] Assignee GAPCorporation New York, N

[54] COLOR OSCILLOGRAlPi-I RECORDING PAPER 6 Cllaims, N0 Drawings [52]US. Cl 96/22, 96/74 [51] Int. Cl G03c 7/16, G03c 1/76, G030 3/00 [50]Field of Search 96/48 OF, 22, 74

[56] References Cited UNITED STATES PATENTS 3,168,400 2/1965 Blackmer etal 96/22 3,212,895 10/1965 Barbier et al. 96/95 3,265,503 8/1966 Bodmeret a1. 96/74 3,372,030 3/1968 Jacobson 3,226,234 12/1965 HimmelmannetalAttorneys-Walter C. Kehm, Samson B. Leavitt and George L.

Tone

ABSTRACT: Light-sensitive multicolor recording paper for oscillographtraces, having on a support, an undercoat of green-sensitivegelatin-silver bromoiodide emulsion in which the iodine amounts to0.2-2.0 mol percent of the silver and containing a magenta color former,a gelatin interlayer, an overlying blue-sensitive gelatin-silverbromoiodide emulsion in which the iodine is 4-12 mol percent of thesilver content and containing cyan color former, and a gelatin surfacecoating. By using yellow and magenta filters of different density forthe exposing light and subjecting the material to color development, atleast three different color traces can be produced.

COILOli OSCHlLlLOGRAPllll RECORDING lPAlPElR This invention relates, ingeneral, to color oscillograph recording materials and, in particular,to photosensitive recording paper which finds immediate and practicalutility for recording oscillograph traces in at least three colors.

Photosensitive papers adapted for light recording, for example,oscillograph recording, are known. Such materials are both of theprintout type and the developing-out type. The printout type of materialrequires no development step and may or may not be fixed. Such materialsare generally much slower than the materials used in developing-outprocesses and have poor image permanency. The developing-out type, asthe name implies, requires that the exposed material be chemicallydeveloped, fixed and washed in order to provide a stable visible imageon said material. It is this second type of printing material with whichthe present invention is concerned.

As light recording, e.g., oscillograph recording has increased inimportance, there have evolved fields of use in which a multicoloredrecording is desirable. Wind tunnel and flight testing are examples ofprocedures where a plurality of colored traces is of considerable value.ldealized trace separa tion and readout of recorded data, of course,improves efficiency of inspection in changing conditions of operationand hence, is desired. Further, test results which can be recorded andvisually observed in a relatively brief interval of time and using asimplified system of processing with a minimum number of solutions isalso desired.

Accordingly, it is an object of this invention to provide a newrecording material for use in oscillograph recording which has anextremely high sensitivity and will improve trace separation andreadout.

Another object of this invention is to provide a simplified system ofprocessing such papers for development employing a minimum numberofsolutions.

A further object of this invention resides in the provision of a colorsystem which closely approximates the handling procedures used withconventional black and white oscillograph papers.

Still another object is a procedure which does not require a bleach stepto remove image silver as required in conventional color systems.

Other objects and advantages of this invention will become furtherapparent from the following detailed description thereof.

in accordance with the above-defined objects, means have been devisedfor the accomplishment thereof which contemplate a photographic materialcomprising, (a) a flexible support bearing on at least one surfacethereof, (b) an undercoat, (c) a separating layer comprising hardenedgelatin, (d) an outer coating and, (e) a hardened gelatin surface layer.

The flexible support is usually photographic paper" or recording paper,which terms are used throughout the specification and claims to includephotosensitive emulsions in any suitable support such as paper, film orother usable medium. ltis preferred, however, to employ a paper such as45-90 grams/square meter Document Paper (100 percent rag) without barytacoat or other surface or a paper similar thereto.

The undercoat layer comprises a silver bromoiodide emulsion which beforeoptical sensitization has a low sensitivity to light having a wavelengthof 480 microns and above. This undercoat layer has an iodide content offrom about 0.2 to 2.0 mole percent, based on the amount of silverpresent in the emulsion. This undercoat is optically sensitized to thegreen region of the spectrum and contains a colorless color former, fastto diffusion, capable of reacting with the oxidation products of anaromatic p-amino developing agent to form a magenta dye image.

The outer coating comprises a silver bromoiodide emulsion layer having ahigh sensitivity to light in the 400-510 micron range when devoid of anyoptical sensitizing dye. The bromoiodide content of this outer layerranges from about 4.0

to 12.0 mole percent based on the amount of silver present in theemulsion. This layer, further, contains a color former capable offorming a cyan dye image upon color development. For best results thesensitivity of the outer coating layer in the wavelength region of 480to 500 microns should be at least two and one-half to three stopshigher, (six to eight times faster) than the corresponding sensitivityof the undercoating layer. l

The invention contemplates conventional photographic recordingtechniques in exposing the photosensitive emulsions to light in aoscillograph recorder. The recorder is necessarily provided withsuitable colored filters in front of galvanometers used in conjunctiontherewith. The conventional photographic recording techniques, generallyreferred to as oscillography, involves the exposure of an entire roll ofa record paper to the information to be recorded with subsequent andseparate chemical development of the roll thus exposed. ln thisprocedure a record roll of approximately 250-400 feet in length isentirely exposed before its removal from the oscillographic recorder andits subsequent development by conventional means.

In accordance with the invention, the color formers employed herein arethose which are well known in the photographic art. The term colorformer is used throughout the specification and claims to define anessentially colorless compound fast to diffusion which is capable ofreacting with the oxidation products of an aromatic p-amino developingagent, particularly of the N,Ndisubstituted p-phenylenediamine series asexemplified by N,N-diethylamino aniline, hydroxyethyl)-aniline and thelike, to produce dyes of the azomethine, quinoneimine, indoaniline andphenazine (azine) series. Such color formers are well known to personsskilled in the art and described in the patent literature, for instancein US. Pat. Nos. 2,500,487; 2,547,307; 2,829,975 and others.lllustrative of the color formers which are usable in accordance withthis invention are compounds such as: l-octadecyl-Z-(Z',l'-hydroxynaphthyl)-benzimidazole-5-sulfonic acid as a cyan colorformer; l-(4-phenoxy-3'sulphophenyl)-3-stearyl- S-pyrazole as a magentacolor former; and2-(4'-benzolylacetoaminophenyl)-1-octadecylbenzimidazole5-sulfonic acidas a yellow color former. Generally speaking, the quantity of colorformer used per unit of silver halide is selected in such a way thatsufficient density of the trace is achieved upon exposure and developingso as to provide proper readout. Specifically, it is recommended thatthe ratio of color former to silver halide per silver halide emulsionlayer be about 10 millimole ofcolor former to about 2 to 20 grams ofsilver halide.

The invention contemplates the use of a sensitizing dye capable ofsensitizing in the green region of the spectrum. If desired, the bluesensitivity of the blue sensitive layer can be further increased by theuse of a sensitizing dye for the blue. It is preferred that these dyesshould be nonmigratory in the emulsion in which they are present so thatthe dyes cannot wander freely from layer to layer. Nonlimiting examplesof sensitizing dyes usable herein are the various cyanine. carbocyanine,merocyanine, styryl and related sensitizing dyes which are well known topersons skilled in the art.

The emulsions may contain the usual coating finals such as thoseproposed to retard or prevent fog in light-sensitive silver halideemulsions. These compounds are commonly referred to as antifoggants orstabilizers and are, in many instances, heterocyclic compounds with aplurality of nitrogen atoms or with a mercapto group in their molecule.

Certain other adjuvants normally incorporated into silver halidephotographic emulsions, such as wetting agents, may also be employed.

In accordance with this invention, it is contemplated to treat theaqueous gelatin dispersions and gelatin silver halide emulsions employedherein with a hardening agent in order to reduce the tendency of thelayers to soften, melt or reticulate during processing, particularly attemperatures which are higher than the temperature of 68 F. (20 C.)previously specified for the processing of photographic materials.Compounds which have been used for the hardening of gelatin and gelatinemulsion layers include formaldehyde, hydroxyaldehyde's, glyoxal and itsderivatives, triacrylformal, as well as mixtures of such aliphaticaldehydes with an aromatic hydroxy compound such as phenol, orresorcylic aldehyde. Other conventional hardeners also applicableinclude alum, chromalum, chromium acetate and the like.

Suitable supports for the novel silver halide emulsions and elements ofthis invention include the flexible supports used in the prior art foroscillographic recordings. These supports may be transparent but, ingeneral, a photographic grade flexible paper is selected. In thisregard, 55 g./m. of Document Paper (100 percent rag) without a barytacoating or other surface coating is especially preferred. However, therecan be used any other flexible material suitable for coating with aphotographic colloid silver halide emulsion.

The invention will be further illustrated by, but is not limited to, thefollowing examples:

EXAMPLE I An improved recording paper was prepared by adding to 1,000grams of a low blue sensitive bromoiodide emulsion containing 1.8 molepercent iodide the following ingredients: 165 cc. of a 122,000 solutioncontaining a sensitizing dye for the green; 7 cc. ofa 2 percent solutionofa triazaindolzinc antifoggant; 60 cc. ofa 10 percent solution of anammonium salt of a sulfate ester of an alkyl phenoxypolyoxyethyleneethanol which serves as a coating aid; 25 cc. of a 6 percent solution ofa triacrylformal hardener; 25 cc. ofa 0.2 percent solution ofatetrazaindene restrainer and 20 grams of a magenta color former havingthe formula:

Thirty grams of gelatin were added to the above ingredients along with1,000 cc. of water so as to adjust it for the proper coating viscosityon 55 g./m. Document Paper (lOO percent rag). This coating was appliedto a thickness corresponding to a metallic silver coating weight of 0.4gram per square meter.

In the same operation but at a different coating station, a 3.0 percentby weight gelatin surface solution containing the above wetting agentand 18 cc./kg. of a 10 percent formaldehyde solution was added.

in a second coating operation to 1,000 grams of a high speed bromoiodideemulsion were added 7 cc. of a 2 percent solution of a triazaindolzincantifoggant', 45 cc. of a 10 percent solution of an ammonium salt of asulfate ester of an alkyl phenoxypolyoxyethylene ethanol which serves asa coating aid; 30 cc. ofa 6 percent solution ofa triacrylformalhardener; and 20 grams ofa cyan color former having the formula:

COOH

Forty (40) grams of gelatin were added to the above ingredients alongwith 1,000 cc. of water so as to adjust it for a proper coatingviscosity. The so-adjusted emulsion was coated on top of the magentalayer to a coating thickness corresponding to a metallic silver coatingweight of about 0.6 gram of silver per square meter.

In the same operation, but at a different coating station, 3.0 percentby weight of the above-described gelatin solution was applied.

The coated material with the two silver halide layers was exposed usinga commercially available oscillograph (manufactured by the MidwesternInstruments Corp.) employing a tungsten light source (2,850 K.) underthe following conditions:

1 Color correction.

The lamp voltage was set at 12 volts and paper travel rate was adjustedat 25 inches/second.

In order to expose the recording paper. signal generators were used toapply a sine wave of 20 cycles/second to each galvanometer and theamplitude was varied to give a trace deflection of from 1 to 4 inches.

The resulting exposed material was then placed in a standard automaticoscillogram processor as manufactured by Consolidated ElectrodynamicsCorp.. and processed at a rate of about 6 feet/minute for a contact timeof about 20 seconds in each tank. In such processor apparatus 4 tankswere utilized, each being maintained at a temperature of about l00 F.,with the following tank arrangement as to contents:

Tank Number Tank Contents I Color Developer (6 liters) 2 Color Developer(4 liters) 3 Fixer (4 liters) 4 Fixer Millers) The availability of twodeveloper and two flxer tanks made it possible to extend the processingtime and to extend the useful life of the processing solution.

in the foregoing the color developer and fixer utilized contained thefollowing ingredients and in the following amounts:

with pH adjusted to 10.6

FIXER Ingredient Amount HYPO (sodium thiosullate, 1300 grams anhydrousWater up to l liter The resulting processed paper showed five distinctand separate traces, namely, magenta, cyan, purple, deep blue and darkmagenta. The magenta trace was produced by the light from galvanometer Awhich was fitted with the yellow filter. The cyan trace was produced bythe light from galvanometer B which was fitted with the magenta filter.The purple trace was produced by the light from galvanometer C which wasfitted with a yellow color-correction filter, the deep blue trace by thelight from galvanometer D, which was fitted with a magenta filter andthe dark magenta trace was produced by the light from galvanometer Ewhich was fitted with a yellow color-correction filter.

It should be noted that in practice the filters selected to produce thevarious desired colored trace lines are determined by the speed of thesensitive material as related to the light source intensity and thecolor temperature. Thus, the above filters were selected for use with atungsten light source. For practical use with an oscillograph using a UVlight source, other filters may be needed especially to balance theso-called white light trace. Nonlimiting examples of the filters whichmay be suitably employed are as follows:

The processing technique employed offers several advantages. Theavailability of two developer and fixer tanks makes it possible toextend not only the developing time and fixing time but also the usefullife of the processing solutions. The omission of the bleaching stepresults in color pictures which contain a warm tone silver deposit. Thepresence of the silver deposit makes it possible to reproduce theoscillograph recording on diazo-type materials.

Modifications of the invention will occur to persons skilled in the art.It is, therefore, not intended to be limited in the patent grantedexcept as necessitated by the appended claims.

What is claimed is:

l. A multicolor recording paper for recording oscillograph traces in atleast three colors which comprises (a) a flexible support bearing on atleast one surface thereof, in the following order: (b) an undercoat of ahardened silver bromoiodide emulsion, having a low sensitivity to lighthaving a wavelength of 480 microns and above, and being opticallysensitized to the green and containing a color former capable of forminga magenta dye image upon color development, said emulsion having aniodide content ranging from 0.2 to 2.0 mole percent based on the amountof silver present, (c) a hardened gelatin intersurface layer, (d) ahardened silver bromoiodide outer emulsion coating which is bluesensitive in the wavelength region ranging from 400 to 510 microns andcontaining a color former capable of forming a cyan dye image upon colordevelopment, the iodide content of said upper emulsion ranging from 4.0to 12 mole percent based on the amount of silver present, and (e) as anouter surface layer, a hardened gelatin layer.

2. The paper of claim 11 in which the silver halide emulsion layers arecoated to a silver coating weight of about 0.4 grams silver per squaremeter.

3. The paper of claim l in which the outercoat silver halide emulsionlayer has a light sensitivity in the wavelength region from 480 to 500microns region which is at least six times higher than that of theundercoat silver halide emulsion layer.

4. The paper of claim 1 in which the magenta color former has theformula:

5. The paper of claim 1 in which the cyan color former has the formula:

COOH

COOH

6. A process of forming a multicolored image which comprises exposingwith a plurality of selectively filtered colored lights, a multicolorrecording paper for recording oscillograph traces in at least threecolors which comprises, (a) a flexible support bearing on at least onesurface thereof in the following order: (b) a hardened silverbromoiodide emulsion, having a low sensitivity to light having awavelength of 480 microns and above, and being optically sensitized tothe green and containing a color former capable of forming a magenta dyeimage upon color development, said emulsion having an iodide contentranging from 0.2 to 2.0 mole percent based on the amount of silverpresent in the emulsion, (c) a hardened gelatin intersurface layer, (d)a hardened silver bromoiodide emulsion coating which is blue sensitivein the wavelength region ranging from 400 to 510 microns and containinga color former capable of forming a cyan dye image upon colordevelopment, the iodide content of said outer coated emulsion layerranging from 4.0 to [2.0 mole percent based on the silver present, and(e) as an outer surface layer, a hardened gelatin layer, developing theimagewise exposed recording material with a color developer solutioncomprising an aromatic diamine developing agent and fixing the colordeveloped material without bleaching and washing the processed material.

2. The paper of claim 1 in which the silver halide emulsion layers arecoated to a silver coating weight of about 0.4 grams silver per squaremeter.
 3. The paper of claim 1 in which the outercoat silver halideemulsion layer has a light sensitivity in the wavelength region from 480to 500 microns region which is at least six times higher than that ofthe undercoat silver halide emulsion layer.
 4. The paper of claim 1 inwhich the magenta color former has the formula:
 5. The paper of claim 1in which the cyan color former has the formula:
 6. A process of forminga multicolored image which comprises exposing with a plurality ofselectively filtered colored lights, a multicolor recording paper forrecording oscillograph traces in at least three colors which comprises,(a) a flexible support bearing on at least one surface thereof in thefollowing order: (b) a hardened silver bromoiodide emulsion, having alow sensitivity to light havIng a wavelength of 480 microns and above,and being optically sensitized to the green and containing a colorformer capable of forming a magenta dye image upon color development,said emulsion having an iodide content ranging from 0.2 to 2.0 molepercent based on the amount of silver present in the emulsion, (c) ahardened gelatin intersurface layer, (d) a hardened silver bromoiodideemulsion coating which is blue sensitive in the wavelength regionranging from 400 to 510 microns and containing a color former capable offorming a cyan dye image upon color development, the iodide content ofsaid outer coated emulsion layer ranging from 4.0 to 12.0 mole percentbased on the silver present, and (e) as an outer surface layer, ahardened gelatin layer, developing the imagewise exposed recordingmaterial with a color developer solution comprising an aromatic diaminedeveloping agent and fixing the color developed material withoutbleaching and washing the processed material.